Apparatus for the contamination-free drainage of clean water in an aircraft

ABSTRACT

An apparatus for the contamination-free drainage of fresh water in an aircraft, the apparatus having a fresh water supply line ( 8 ) with a fresh water outlet ( 2 ) from which water issues during drainage, and disposed downstream thereof an inlet opening ( 4 ) of a line ( 9 ), the inlet opening being provided for receiving drainage water and the line ( 9 ) being connected to the waste water system of the aircraft, and the fresh water outlet ( 2 ) and the inlet opening ( 4 ) being disposed in a housing ( 1 ) which has an overflow ( 7 ).

The invention relates to an apparatus for the contamination-free drainage of fresh water in an aircraft.

In commercial aircraft, fresh water, that is, drinking water is carried onboard in one or more drinking water tanks and is available to the passengers or crew of the aircraft via a line system at defined dispensing points, for example at water taps.

It is generally advantageous if the fresh water tank can be selectively emptied. A known method of carrying out such drainage of fresh water is an open water jet between a fresh water outlet and a waste water inlet funnel through which the fresh water can be passed into the onboard waste water system. The free water jet is used in order to avoid back-contamination from the waste water system into the fresh water system. A problem with this is that no security is afforded against overflow and so the aircraft is possibly put at risk upon fresh water drainage during a flight, which is why such drainage is not suitable for use in flight.

An alternative drainage possibility is to lay drinking water drainage lines to the existing drainage orifices in the aircraft fuselage, also referred to as “drain ports”. This, however, may involve greater expenditure on construction and is not suitable for drainage of large quantities of water. Furthermore, such drainage cannot be employed in flight since in flight the water could run along the fuselage unchecked and could freeze. Ice could come off and damage parts of the aircraft, for example leading edges of the wings.

As a third possibility, an outboard, additional fresh water discharge nozzle (drain mast), including supply line and regulated motor valve, may be provided. Those drain masts are heated and direct the waste water into the airstream beneath the fuselage of the aircraft, where it evaporates/vaporises. In that manner, drainage of large quantities of water may also take place in flight, but this method does involve a high complexity and high costs. Furthermore, an additional drain mast may worsen the aerodynamics of the aircraft, which may result in increased fuel consumption.

The object of the invention is accordingly to provide an apparatus for the contamination-free drainage of fresh water in an aircraft, which apparatus is especially simple and inexpensive.

The invention attains that object by means of an apparatus having the features of claim 1. Additional preferred embodiments of the invention will be apparent from the subordinate claims and the associated description and from the drawings.

To attain the object, an apparatus for the contamination-free drainage of fresh water in an aircraft is proposed, the apparatus having a fresh water supply line with a fresh water outlet from which water issues during drainage and, disposed downstream thereof, an inlet opening of a line, the inlet opening being provided for receiving the drainage water and the line being connected to the waste water system of the aircraft. According to the invention, the fresh water outlet and the inlet opening are disposed in a housing which has an overflow.

By means of the apparatus according to the invention, the passage of water from the fresh water outlet to the inlet opening is transferred to a closed housing, whereby the fresh water outlet is better shielded from external influences (dirt, air that may possibly contain bacteria) and thus protection from contamination of the fresh water system is increased. In addition, the overflow in particular ensures that it is not possible for so much water to collect in the housing that back-contamination of the fresh water system occurs. The overflow line attached to the overflow is able to take overflowing water away to a safe region of the aircraft and can thus provide that there can be no germ-transferring, simultaneous contact of the water with the fresh water outlet and the inlet opening. By means of the apparatus according to the invention, the existing waste water system on the aircraft may be used in an especially simple and inexpensive manner for the contamination-free drainage of fresh water and, at the same time, uncontrolled overflowing is avoided.

Preferably, the apparatus is free of electrics, electronics and/or mechanical elements. In that manner, the apparatus is less susceptible to possible faults. The drainage of the fresh water therefore takes place preferably only through the inlet opening disposed in the housing and through the overflow. It is advantageous if the inlet opening is in the form of a funnel. An inlet opening in the form of a funnel is also advantageous with regard to the drying effect which will be described later.

Preferably, the fresh water outlet is disposed at the lid of the housing or is part of the lid. Owing to the integration of the fresh water outlet in the lid of the housing, the apparatus according to the invention is compact and saves on installation space. That effect is intensified if the inlet opening is preferably disposed at the base of housing or is part of the base, and the apparatus may in that manner be of an even more compact configuration. It is advantageous if a gap is provided between the fresh water outlet and the inlet opening since in that manner it is possible to ensure that no back-contamination is able to occur if the inlet opening fills up.

Preferably, the central axes of the inlet opening and of the fresh water outlet are concentric. By means of that arrangement, in which the fresh water outlet is provided directly above the inlet opening, drainage is able to take place well since little splashed water goes past the inlet opening into the overflow. That effect is intensified if the central diameter D_(E) of the inlet opening at the end towards the fresh water outlet is at least half the size of and more preferably greater than 75% of the size of the outside diameter D_(G) of the housing, since in that manner almost all of the water issuing from the fresh water outlet is also captured by the inlet opening and conveyed away.

Preferably, the overflow is disposed at the base of the housing or is part of the base. Arranging the overflow at the base of the housing or as part of the base is advantageous since in that manner no water is able to collect in the base region, but rather the water is conveyed away directly into the overflow line. Furthermore, if no fresh water is being drained, air is able to flow via the overflow line from the base of the housing into the housing and from there is able to flow further through the line into the waste water system and from the waste water system to the waste water discharge nozzle (drain mast) mounted on the outboard side. Owing to the pressure difference between the cabin and the surrounding area during flight, the airstream always goes only in the described direction and in so doing dries the base of the housing and further walls of the housing, and especially the inlet opening on the inside. That drying effect counteracts the formation of a biofilm in the housing and especially on the inlet opening, since without water the bacteria forming the biofilm cannot settle on the surface, or can settle only to a very limited extent, and are unable to multiply.

Preferably, at least one ventilation bore is provided in the housing. Ventilation bores are able to intensify the drying effect described in the foregoing and, in addition, are able to influence the airstream in such an advantageous manner that air flows over regions of the housing and/or of the inlet opening that it would otherwise flow over only to a limited extent. This additionally counteracts the formation of a biofilm, which, in view of the considerable damage that can be caused by biofilms, is especially advantageous.

Preferably, the fresh water supply line has a valve which must be opened for draining. As described again in detail later, a fresh water supply line with a valve is especially well suited to carrying out fresh water drainage when the aircraft is on the ground.

Preferably, the overflow line attached to the overflow is equipped with a water-detecting device which is so configured that it automatically sends a signal to the valve in the event of water overflowing, whereupon the valve closes and the drainage of fresh water is reduced or completely stopped. Implementing such a water-detecting device makes it possible to prevent a lot of water from overflowing inadvertently.

Preferably, a water level measuring device is disposed at the inlet opening, which sends a signal to the valve in dependence on the water level in the inlet opening, whereby the rate of flow of the fresh water is reduced by the valve. By using such a water level measuring device, which may, for example, be in the form of a float, drainage can be slowed down or stopped even before an overflow of water occurs and thus an excessively high water level and/or overflowing can be avoided. Preferably, the fresh water drainage is therefore regulated by the water level measuring device, which is suitable especially for the drainage of large quantities of water in flight.

It is further preferred for an overflow opening, through which the water is able to flow into the overflow, to be disposed below the (preferably funnel-shaped) inlet opening. Preferably, the opening of the overflow is disposed in the base of the housing, so that any overflowing water is able to flow away out of the inlet opening and into the overflow without water collecting at the base of the housing.

The invention is described below with the aid of advantageous embodiments with reference to the accompanying Figures, in which, in detail:

FIG. 1 shows a prior art lavatory compartment of a commercial aircraft with fresh water drainage,

FIG. 2 is a sectional view of an apparatus according to the invention for the contamination-free drainage of fresh water for an aircraft,

FIG. 3 is an illustration of an installation plan of an apparatus according to the invention with additional valve and with a water-detecting device.

FIG. 1 shows a lavatory compartment of a commercial aircraft in which drainage of fresh water takes place by the known method. In that case, an open water jet 22 is used between a fresh water outlet 2 of a fresh water supply line 8 and an inlet opening 4 of a waste water line 10. The open water jet 22 is intended to prevent back-contamination of the fresh water outlet 2 and of the fresh water supply line 8.

A problem with such drainage according to the prior art is that no security is afforded against overflow and so the aircraft could possibly be put at risk upon fresh water drainage during a flight, which is why fresh water drainage of that kind is not suitable for use in flight.

FIG. 2 is a sectional view of an apparatus according to the invention for the contamination-free drainage of fresh water for an aircraft. In the case of such a drainage unit 25, a fresh water supply line 8 leads into a fresh water outlet 2 which is preferably disposed in the lid 3 of a preferably cylindrical housing 1. An inlet opening 4 is also disposed in the housing 1 preferably at the base 5 or as part of the base 5, which inlet opening 4 is in its preferred form of embodiment here as a funnel and extends from the base 5 as far as the middle of the housing. In this case, the central diameter D_(E) of the inlet opening 4 increases constantly from the base 5 to its end 23 associated with the fresh water outlet. The gap 6 between the fresh water outlet 2 and the end 23 of the inlet opening 4 is preferably always positive, that is, the fresh water outlet 2 is not situated inside the funnel but is disposed remote from it by a gap 6 so that, if the funnel fills up, no water is able to come into contact with the fresh water outlet 2. Accordingly, the apparatus is preferably so arranged that the fresh water travels a free distance. By means of the free distance and the overflow 7 it is possible to counteract back-contamination.

So that the water may be conveyed away in the event of the funnel overflowing, an overflow 7 capable of conveying water away via an attached overflow line 13 is preferably formed as part of the base 5 or disposed in the base 5 of the housing 1. As shown in FIG. 2, the overflow opening 7 a of the overflow 7 is disposed below the inlet opening 4 of the line 9.

From the funnel, the drained water is passed into a line 9 which is connected to the waste water system of the aircraft.

As illustrated in FIG. 2, the funnel is preferably disposed inside the housing 1, and is therefore preferably completely enclosed by the housing 1.

When no fresh water drainage is taking place, it is possible, especially during flight, for an airstream 11 to flow via the overflow line 13 and the overflow 7 into the housing 1 and from there into the line 9 through the inlet opening 4. The air continues to flow in the line 9 via the waste water system of the aircraft as far as the waste water discharge nozzle 24 mounted on the outboard side, since owing to the flight altitude there is a distinctly lower pressure in the area surrounding the aircraft than in the interior of the aircraft cabin (see FIG. 3). By means of the airstream 11 the overflow line 13, the overflow 7, the interior of the housing 1 and especially the inlet opening 4, and all other surfaces over which it flows are dried. That drying effect counteracts the formation of a biofilm since without water the bacteria forming the biofilm cannot settle on the surface, or can settle only to a very limited extent, and are unable to multiply.

That drying effect can be intensified by ventilation bores 14 or a single ventilation bore 14 provided in the housing 1, which are/is preferably disposed in the lid 3 of the housing 1 and especially preferably on the side opposite the overflow 7. By means of a ventilation bore 14 disposed in the lid 3 and as far as possible diametrically opposite the overflow 7 provided in the base 5 an additional airstream 11 a may be specifically generated in such a way that it also flows over regions in the housing 1 that the first airstream 11 flows over only to a limited extent. Disposing the overflow 7 in the base 5 has the advantage that the latter is dried especially well by the airstream 11.

So that an especially large quantity of fresh water flows from the fresh water outlet 2 into the inlet opening 4, the central diameter D_(E) is preferably at least half the size of and especially preferably greater than 75% of the size of the outside diameter D_(G) of the housing 1.

Beneath the underfloor region 20 there is the fuselage region 15, also called the bilge, of the aircraft, into which the water from the overflow line 13 is preferably led away. Disposed beneath the fuselage region 15 is the waste water discharge nozzle 24, the so-called drain mast, of the aircraft, into which the fresh water from the fresh water line 8 is led via the drainage unit 25 and the line 9. The airstream 11 also leaves the aircraft via that waste water discharge nozzle 24.

Alternatively, the overflow line 13 may also be led back into the line 9 again instead of being led away into the bilge.

As illustrated in FIG. 3, the drainage unit 25 is preferably mounted in the underfloor region 20 of a commercial aircraft. That advantageous arrangement makes simple drainage possible since in many aircraft the fresh water system 21 and the fresh water lines are positioned in the deck region of the aircraft cabin 12. This is the case, for example, with the Boeing 737—(BBJ) and B777 types of aircraft. For design reasons, the water cannot in that case be passed directly from the fresh water system 21 in the deck region to the water tap, in particular because it also has to pass through a continuous flow heater which is also situated below the water tap. This means that, after the water tap has been opened, residual water always remains in the fresh water supply line 8 which—for the design reasons mentioned—is situated below the water tap. That fresh water supply line 8 is emptied in a drainage operation in the B737 and 777 via the drain ports described in the introduction, in order to avoid contamination of the standing water. This requires, however, on the one hand a drain port which also has to be additionally connected by means of lines. When the apparatus according to the invention is used, however, only a connection to the waste water system is necessary and furthermore drainage of drinking water can also take place in flight without the installation of additional drain masts.

Drinking water drainage operations in flight are carried out in order to discharge surplus drinking water, which may be sensible on night flights, for example, since experience shows that less water is required then and hence weight and therefore fuel consumption can be reduced. In addition, drainage of drinking water may also be carried out shortly before landing so as to avoid drainage of drinking water on the ground, since this is a problem particularly in cold regions because the water quickly freezes during drainage if the aircraft is not heated, which again is expensive and also costs fuel.

According to the invention, a water-detecting device 17 is preferably disposed in the overflow line 13. In addition, a valve 16, which may preferably be driven by a motor 18, is disposed in the fresh water line 8. The water-detecting device 17 is preferably connected to the motor 18 of the valve 16 via a relay 19. The motor-operated valve 16 is preferably closed automatically as soon as the water-detecting device 17, which is preferably in the form of a water sensor, detects water and passes a signal to the motor 18 via the relay 19. The apparatus according to the invention may also be configured in such a way that the valve 16 does not close completely but rather only the rate of flow of the water is reduced. In addition, the fresh water line 8 may be equipped with a cross-section-reducing element in order to limit the quantity of water flowing into the housing 1.

In addition or alternatively to the water-detecting device in the overflow line, a water level measuring device may also be disposed at the inlet opening 4, which sends a signal to the valve 16 or rather to the motor 18 of the valve in dependence on the water level in the inlet opening 4, whereby the flow rate of the fresh water is reduced. The water level measuring device is preferably in the form of a float and sends the signal to reduce the flow rate at a predetermined water level. Thus, fresh water drainage can be stopped in good time before an overflow occurs.

The water-detecting device 17 and the water level measuring device are suitable especially for the drainage of large quantities of water in flight since with them it is possible to make the drainage overflow-proof.

The fresh water line 8 and/or the line 9 and also the drainage unit 25 are preferably insulated and/or electrically heated to eliminate the risk of freezing.

The apparatus according to the invention for the contamination-free drainage of fresh water thus makes it possible to carry out fresh water drainage in an especially simple and inexpensive manner on the ground and in the air, since the fresh water can be passed into the onboard waste water system and no elaborate measures need to be taken, such as the installation of an additional drain mast. 

1. An apparatus for the contamination-free drainage of fresh water in an aircraft, the apparatus having a fresh water supply line with a fresh water outlet from which water issues during drainage, and disposed downstream thereof an inlet opening of a line, the inlet opening being provided for receiving drainage water and the line being connected to the waste water system of the aircraft, wherein the fresh water outlet and the inlet opening are disposed in a housing which has an overflow.
 2. An apparatus according to claim 1, wherein the inlet opening is in the form of a funnel.
 3. An apparatus according to claim 1, wherein the fresh water outlet is disposed at the lid of the housing or is part of the lid.
 4. An apparatus according to claim 1, wherein the inlet opening is disposed at the base of the housing or is part of the base.
 5. An apparatus according to claim 1, wherein the central axes of the inlet opening and of the fresh water outlet are concentric.
 6. An apparatus according to claim 1, wherein the central diameter D_(E) of the inlet opening at the end towards the fresh water outlet is at least half the size of and more preferably greater than 75% of the size of the outside diameter D_(G) of the housing.
 7. An apparatus according to claim 1, wherein the overflow is disposed at the base of the housing or is part of the base.
 8. An apparatus according to claim 1, wherein at least one ventilation bore is provided in the housing.
 9. An apparatus according to claim 1, wherein the fresh water supply line has a valve (16) which must be opened for draining.
 10. An apparatus according to claim 9, wherein the overflow line attached to the overflow is equipped with a water-detecting device which is so configured that it automatically sends a signal to the valve in the event of water overflowing, whereby the drainage of fresh water is reduced or completely stopped.
 11. An apparatus according to claim 9, wherein a water level measuring device is disposed at the inlet opening, which sends a signal to the valve in dependence on the water level in the inlet opening, whereby the rate of flow of the fresh water is reduced.
 12. An apparatus according to claim 1, wherein an overflow opening, through which the water is able to flow into the overflow, is disposed beneath the inlet opening. 